Despite the generality of Eq. (REF ), the moderate
signal-to-noise ratios (SNRs) of most LIGO-Virgo observations, so
far, do not allow us to place meaningful bounds on multiple
deviation parameters concurrently. Hence, we vary one parameter at
a time, keeping the rest fixed at their nominal GR prediction,
which is zero. This assumption is validated by
investigations [1]}, [2]}, [3]}, [4]} that conclude that a signal
containing deviations at several PN orders is likely to lead to a
non-zero deviation measurement using a model with only a single
deviation parameter. On the other hand, a recent
work [5]} following a principle component
analysis identified certain combinations of these deviation
parameters with the tightest constraints; in fact, the two
dominant principle components rather capture the essence of the
full multi-parameter test.
